implementing Testing Event Emitters in Angular Components Using Jasmine
I'm updating my dependencies and I'm having trouble unit testing a component in Angular that utilizes an EventEmitter to communicate with its parent component. Specifically, I'm trying to verify that the correct event is emitted when a method is called, but I'm getting inconsistent results. My component looks like this: ```typescript import { Component, EventEmitter, Output } from '@angular/core'; @Component({ selector: 'app-example', template: `<button (click)="triggerEvent()">Click me</button>` }) export class ExampleComponent { @Output() exampleEvent = new EventEmitter<string>(); triggerEvent() { this.exampleEvent.emit('Hello World'); } } ``` In my test file, I'm trying to set up the test like this: ```typescript import { ComponentFixture, TestBed } from '@angular/core/testing'; import { ExampleComponent } from './example.component'; describe('ExampleComponent', () => { let component: ExampleComponent; let fixture: ComponentFixture<ExampleComponent>; beforeEach(() => { TestBed.configureTestingModule({ declarations: [ExampleComponent] }); fixture = TestBed.createComponent(ExampleComponent); component = fixture.componentInstance; }); it('should emit exampleEvent with correct value when triggerEvent is called', () => { spyOn(component.exampleEvent, 'emit'); component.triggerEvent(); expect(component.exampleEvent.emit).toHaveBeenCalledWith('Hello World'); }); }); ``` However, when I run my tests, I occasionally see this behavior message: `Expected spy emit to have been called with ["Hello World"], but it was never called.` This seems to happen intermittently, and I want to figure out why. I've tried moving the test setup and execution into `beforeEach` and `it` blocks but that didn't solve the scenario. I'm using Angular version 12 and Jasmine for testing. Is there something I'm missing in how to correctly test the EventEmitter? Are there best practices for setting this up that I might be overlooking? Is there a better approach? The stack includes Typescript and several other technologies. Has anyone dealt with something similar?